1. Field of the Invention
The present invention relates to a side sliding door device that opens and closes an entrance or opening on a side of a railway vehicle, for example, a train, and more particularly to a locking mechanism that locks a sliding door in a closed state.
2. Background of the Invention
Side sliding door devices for a train fulfill an important role in protecting passengers' lives, and must not be freely operated regardless of whether the train is moving or not, and require high operational reliability. In general, a side sliding door device has a sliding door driven by an actuator at each entrance. The sliding door is automatically locked in a closed state by an automatic locking mechanism when a closing operation is completed, and unlocked by an electric actuator, for example, an electromagnetic actuator, operated according to a sliding door opening instruction when an opening operation is performed.
If a problem trouble occurs in an opening/closing instruction system while the sliding door is operated, and, for example, the sliding door does not perform the opening operation even if the opening instruction is provided, the automatically locked sliding door is likely to be unlocked by an operational error of the electric actuator. For such abnormal conditions as this, a manual locking mechanism is separately provided. The manual locking mechanism mechanically locks the sliding door by a manual operation in the abnormal conditions, and avoids the risk of unlocking even if any electrical problems occur.
FIGS. 10 to 13 show a prior art example of the manual locking mechanism. FIG. 10 is a front view thereof in an unlocked state, FIG. 11 is a partial sectional view taken along the line XI—XI in FIG. 10, FIG. 12 is a front view thereof in a locked state, and FIG. 13 is a partial sectional view taken along the line XIII—XIII in FIG. 12. In FIGS. 10 to 13, a manual locking mechanism 50 has a manual rotary (cylinder) lock 51 and a lock lever 52 integrally secured to a rotation axis thereof, and is secured to a column 54 on a side of an entrance of a train vehicle body via a fastener 53 having a horseshoe-shaped section. The manual locking mechanism 50 is placed, for each door of the double sliding doors 1, 2 (the manual locking mechanism 50 for the sliding door 2 only is shown), adjacent to a back end surface of each of the sliding doors 1, 2 shown in a closed state.
In FIGS. 10 and 11, the lock lever 52 is in an upright state, and does not prevent an opening operation of the sliding door 2 to the right. FIGS. 12 and 13 show a state in which the rotary lock 51 is rotated through 90° by an unshown key inserted from a keyhole in the left end surface as shown in the drawings. The lock lever 52 protrudes behind the rear end surface of the sliding door 2. In this state, the sliding door 2 is held by the lock lever 52, and cannot perform the opening operation from the shown closed state. In FIG. 13, reference numeral 55 denotes a back-up block for the lock lever 52 which is secured to a column 56 of the vehicle body. As described above, the manual locking mechanism 50 is manually operated by a conductor in abnormal conditions to lock the sliding door 2 in the closed state by the lock lever 52. The locking is mechanically performed to prevent the possibility of unlocking caused by an electrical problem.
However, the prior art has a structure in which movement of the sliding door is restricted by the manual locking mechanism mounted to the vehicle body. Thus, manufacturing errors of the sliding door influence mounting positions of the manual locking mechanism. As a result, it takes substantial time to perform positional adjustment of the manual locking mechanism for each sliding door at the site where the vehicle is used. For example, if two sliding doors are placed at each of four entrances on one side, one vehicle includes 16 sliding doors, and the adjustment operation requires a large number of steps.